The magnetic CV Swift J0614.0+1709 is not the optical counterpart of Fermi J0614+1713

Abstract

The Fermi-LAT Gamma-ray Transient Fermi J0614+1713 was detected over 3.5days starting from Jan 28, 2022 with an improved localization of 0.17deg centred at RA=93.48 and DEC=17.18 (ATels #15196, #15199) encompassing the magnetic CV SwiftJ0614.0+1709. We analysed the optical light curve of SwiftJ0614.0+1709 in the ASAS-SN photometry database (Shappee et al. 2014, ApJ 788, 48) with an almost daily coverage up to Feb 6, 2022. In particular it has been observed on Jan 28 from 04:24 to 05:16UT, on Jan 29 from 05:43 to 05:47UT, on Jan 30 from 07:44, on Feb. 03, 2022 from 00:56 to 08:37UT, on Feb. 04 from 02:04 to 09:42UT and on Feb. 6 from 04:08 to 04:56UT. Aperture photometry reveals SwiftJ0614.0+1709 at a stable level with a mean g-band magnitude of 17.13 (rms=0.19), consistent with the Gaia eDR3 measurement (G=17.10) and previous optical measures (Halpern & Thorstensen, 2015, AJ 150, 170). Therefore this mCV is excluded as the counterpart of the Fermi transient. The analysis of about two hundreds optical sources observed by ASAS-SN during the same period located within the 0.17deg localization uncertainty of the gamma-ray source is ongoing.